Current-ballasting device



Nov. 6, 1928.

A. W. ZIEGLER CURREN'J. BALLASTING DEVICE Filed O t. 1925 A /2 l w 7 @7hue/#0? Arf/wr H. Z/y/er by Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

ARTHUR WILLIAM ZIEGLER, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOR TO WEST-ERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y.. A CORPORATION Q1NEW YORK.

CURRENT-BALLASTING DEVICE.

' Application filed October 5, 1925. Serial No. 60,476.

This invention relates to current ballasting devices and has particularapplication to the type employing an iron wire resistance element.

It has for an object to provide a current ballasting device which iseasily constructed, possesses long life and operates efficiently over awide rangeof voltages.

In the operation of a plurality of vacuum tubes it is usually customaryto employ a single source of potential to supply heating current to allthe filaments of said tubes. In many cases in such operations, it isdesirable to regulate the heating current supplied very closely andcurrent ballasting devices may then be connected in series with a sourceof potential for this purpose. One type of current ballasting orregulating device which has been heretofore employed is the iron wireballast lamp comprising an iron wire resistance mounted in a chambercontaining an inert gas, such as hydrogen. A discussion of the theoryand uses of such a ballastiiig vice may be had from an article by A.Jones in the General Electric Review for Ma 1925 page 329.

uch devices, however, have a limited voltage range of effective orefiicient operation and when operating over their maximum effectiverange require greater care in their manufacture than .is suited foreconomical commercial production. Furthermore, the life of this type ofballast device has been found to depend substantially upon thetemperature at which it operates or upon the voltage impressed upon it,and decreases rapidly as the operating voltage approaches the maximumefiective voltage.

A feature of the invention comprises a ballast lamp of the iron wireresistance type having two or more filaments adapted to be connected inseries and shunts for normally shunting a predetermined number of saidfilaments and means for opening the shunt across one of said filamentswhen the voltage impressed upon the device exceeds the effective voltageof the filament in operation. Such a device may be connected for examplein series with the source of heating currents for vacuum tube filamentsto regulate the filament current within narrow .lirnits over a widerange of voltages.

Another feature of the invention is the use of a plurality of singlefilament lamps in place of multiple filaments in a single lamp asdescribed above.

A fuller understanding of the invention will be had from the moredetailed description to be given in connection with the accompanyingdrawings in which the same reference characters represent similar parts.

Fig. 1 shows a ballasting device comprising a multiple filament ballastlamp in accordance with one feature of the invention connected so as toregulate the filament current of a plurality of vacuum tubes connectedin tandem.

Fig. 2 shows the manner in which the plurality of single filamentballast lamps may be connected to operate in place of the multiplefilament lamp of Fig. 1.

Referring to Fig. 1 of the drawings, a plurality of vacuum tubes 1comprising anodes 2, control electrodes 3, cathodes 4 are shownconnected in tandem as is well understood in the art. Heating current issupplied to the cathodes 4 from a source of potential 5, through aretard coil 6, a suitable t'use 7 and a current ballasting device. Theretard coil 6 operates to eliminate noises by ofi'setting suddenfluctuations in the battery current. In accordance with the invention,the ballasting device may comprise a ballast lamp 8 having filaments 9and 10 adapted to be connected in series in the filament heating circuitand a high-resistance marginal relay l1 and a shunt 12 normally placedacross one filament, 10 for example. Relay 11 is designed to operatewhen the potential across the circuit exceeds the effective operatingvoltage of filament 9. \Vhen relay 11 operates it opens shunt 12 therebyconnecting filaments 9 and 10 in series.

I'Vhen a multiple filament ballast lamp as described above is employedfor the primary purpose of regulating the filament current withinextremely narrow limits, the first filament as filament 9 is preferablymade longer than the second filament as filament 10 so that the changein the ballasting filament temperature resulting when relay 11 operatesis not such as to cause an appreciable change in the ballasted current.

Furthermore, it is known that the life of a ballast lamp filament isdependent primarily upon the temperature or voltage at which it operatesand that the life is greatly shortened as the operating voltageapproaches or exceeds the maximum of the effective range. In thearrangement according to this invention, therefore, the life issubstantially ncreased and the tendency for the characteristics for alamp to change decreased, since the filaments operate at temperatures orvoltages appreciably below their individual e ective maxima.

In the arrangement of Fig. 2 a plurality of single filament ballastlamps 13 and'let are substituted for the multiple filament lamp 8. As inthe first arrangement, a relay 11 is employed to place the lamps 13 and14 in series when the applied potential difference exceeds the effectivevoltage of lamp 13 by attractlng its armature 12, which in itsun'attracted position shunts lamp 1%.

The filaments of the multiple filament lamp or of the single filamentlamps are composed of some metal having a positive temperaturecoefficient such as ure iron wire and are mounted in a cham ercontaining an inert atmosphere such as hydrogen. A suitable lamp for useover a voltage range of from 2- to 9 volts might be, for example, twofilaments of pure iron wire approximately six centimeters long and .0096centimeters in diameter, in an atmosphere of hydrogen under a pressureof 20 millimeters of mercury. As an example of a satisfactory lamp foruse when it is desired to maintain current within extremely narrowlimits, a lamp having its first filament 6 centimeters long and a secondfilament 3.8 centimeters long, both filaments being approximately .0096centimeters in diameterin an atmosphere of hydrogen under a pressure of15 millimeters of mercury may be used.

It will be evident that other suitable contact making devices, such ascontact makin voltmeters, may be substituted satisfactorily for themarginal relay shown herein.

It is also evident that the methods of ballasting currents in accordancewith the invention may be modified to include the use of more than twofilaments in a single lamp or the use of any number of ballast lampscontaining single filaments. Similarly, the relay or relays operatingthe shunt or shuntspart of the circuit where le; in some cases,therefore, a sin le relay or contact makin device with a mu tiplicity ofcontacts may fie preferable where more than two filaments or singlefilamentballast lamps are employed.

he arrangements of the present invention have been found to berticularly adapted for use for current regu ation within narrow limitsover a wide range of voltage as desired. Tests have shown, for example,that the device represented in Fig. 1 may be employed to maintain thecurrent within a variation of 10% over a voltage variation greater than800%; further, if only the most efiicient opmay be placed in any it mayseem desira g increasing the range of effective changes in said circuitnecting additional of said elements in series crating range of thedevice was considered, the current was found to be maintained with 1.7%over a potential change of 250%.

While the invention has been described herein with reference to aparticular type of regulating device and to a particular type of circuitto be regulated, it will be that it is not intended to limit theinvention to these applications alone, but that of the invention aresusceptible of various adaptations and modifications within the scope ofthe ap 'nded claims.

The term e ective voltage is employed herein to define any voltagewithin the range of applied voltages over which the device will maintainthe ballasted current substantially constant.

What is claimed is:

1. In combination, an electrical circuit, a source of potential for saidcircuit, a plurality of ballasting elements adapted to be connected inseries in saidcircuit, one of said elements being normally connected insaid circuit, means for increasing the range of effective ballasting,said means comprising means connected in parallel with said one elementand acting in response to voltage changes in said circuit for connectinganother of said elements in ment when the voltage across said circuitexceeds the effective ballasting range of the said one element.

2. In combination, an electrical circuit, a source of potential for saidcircuit, a ballasting arrangement, said arrangement comprising)aplurality of ballasting elements adapted to e connected in series insaid circuit, each of said elements having a positive temperaturecoeflicient, and one of said elements being normally connected in saidcircuit, means for ballasting of said arrangement, said means comprisingmeans connected in parallel with said one element and acting in responseto voltage for successively conwith said one element when the voltageacross said circuit exceeds the effective ballasting voltage of theballasting means already in said circuit.

3. In combination, an electrical circuit, a source of potential for saidcircuit, an iron wire ballasting element comprising a plurality of ironwire filaments adapted to be connected in series with said source, oneof said filaments being normally connected in said circuit, meansconnected in parallel with said one filament and changes in said circuitfor connecting another of said filaments in series with said circuitwhen the voltage across said circuit exceeds the effective ballastingvoltage of the said one filament.

4. In combination, a plurality of electron discharge devices, each ofsaid devices havacting in response to voltage all features series withsaid one eleing an anode and a cathode, a source of potential forsupplying heating current to said cathodes, a ballasting arrangement forregulating said heating current over a wide range of voltages, saidarrangement comprising a plurality of iron wire icsistance ballastingelements adapted to be connected in series,

one of said elements being normally comiected in series with saidsource, and means for increasing the range of efiective ballastmg ofsaid arrangement, said means connected in parallel with said one elementand acting in response to voltage changes in said source for bringingadditional of said elements into serious relation with said source whenthe voltage across said source exceeds the effective ballasting Volta, eof said one element.

In witness w ereof, I hereunto subscribe my name this 3rd da of October,A. D. 1925.

AR UR W. 'ZIEGLER.

